Re: ffi.copy/ffi.string fails with volatile-qualified char array
- From: Justin Cormack <justin@xxxxxxxxxxxxxxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Mon, 4 Nov 2013 13:21:19 +0000
On 4 Nov 2013 13:14, "Mike Pall" <mike-1311@xxxxxxxxxx> wrote:
>
> Justin Cormack wrote:
> > Does LuaJIT respect volatile semantics in terms of (not) optimising it?
>
> No, but that's an orthogonal issue to the original question.
>
> ['volatile' is rather complex to implement correctly and the weak
> guarantees are pretty useless on a modern CPU. Memory barriers and
> optimization barriers are conceptually much cleaner. The latter
> are already implemented internally (XBAR), but there's no API to
> emit them explicitly. But then ... nobody asked for those, yet.]
>
Yes sorry about the question hijacking that's what I thought but its been
something I meant to check.
Can we have an API for barriers please... Need them for hardware access and
shared memory access...
Justin
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